374 L. F. Ward — Fossil Dicotyledonous Leaves. 



theoretically far superior to the one we already have must 

 nevertheless see that the attempt, in the existing condition of 

 things, to supplant the latter by the former, or even to engraft 

 the former on the latter, will be attended by grave practical 

 difficulties. Dr. Nathorst speaks as though he had only refer- 

 ence to the future — to genera }'et to be discovered and created. 

 But it does not seem possible thus to limit it. There are now 

 hundreds, probably a thousand, species referred to living genera 

 which his rules would exclude. Are these to be left as they 

 are ? If this is attempted and the new method applied to sub- 

 sequent species it will at once be found that species undoubt- 

 edly belonging to the same genus will be classed under two 

 genera. We shall have Fagus and Fagiphyllum, Quercus and 

 Querciphyllum, Salix and Saliciphyllum performing one and 

 the same role in two parallel series. It is therefore clear that 

 if the change is introduced at all it must be made retrospective. 

 This, however, cannot properly be done except by the previous 

 preparation of a systematic work in which all the cases shall 

 be collected and unified. Under the present system of inde- 

 pendent monographing of special floras unlimited confusion 

 must result from any attempt to apply these new rules of nam- 

 ing. But the nomenclature of paleobotany is already in a be- 

 wildering state. Only to-day I met with a case in which no 

 less than five different plants have been described under the 

 same name (Odontopteris neuropteroides), two of these by one 

 author from the same State, and the Mesozoic and Cenozoic 

 species are only less confounded than the Paleozoic, so that it 

 certainly is ample time that some all-embracing scheme of sys- 

 temization were adopted. But as regards the plan proposed by 

 Nathorst, which, it will be observed, differs but slightly in form 

 and still less in principle from that suggested by Eossmassler in 

 1840, it is evident that before any steps can be taken looking 

 to its introduction paleobotanists must know better how it is 

 to be applied to the existing state of the science and what is to 

 be done with the species already referred, however improperly, 

 to living genera. 



The chief objection that lies against Phyllites is that instead 

 of denoting a natural genus it includes a great number of 

 wholly unrelated genera. The use of the suffix Phyllum might 

 often be open to the same objection. Two generically distinct 

 forms might both resemble a living genus but manifest their 

 deviation from it in precisely opposite directions. We should 

 then have two clearly distinct genera bearing the same generic 

 name. 



The principle of creating extinct genera, the names of which 

 connote their relationships with living ones has long been rec- 

 ognized by the use of the terminations ites, oides, opsis, etc., 

 and some of these are founded on leaf specimens. Such would 



